After some investigation I discover that:
- Store user info in USER_ table
- For each USER_ row there are a row in GROUP_ table, where personal sites url are
- On user cration Liferay use username to generate a friendly url
- this url have to be validated, and one rule is that must be unique
My problem was that I deleted the USER_ row only, so whe I tried to recreate deleted user control on GROUP_ table failed.
So I solved with:
- GROUP_ row deletion (the one whit / on friendly url column)
- Liferay restart